335/35R18 vs 355/35R18
Going from one to the other changes the overall height by +2.0 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 335/35R18 | 355/35R18 | Change |
|---|---|---|---|
| Overall height | 27.2" | 27.8" | +2.0 % |
| Sidewall | 4.62" | 4.89" | +6.0 % |
| Section width | 335 mm | 355 mm | +6.0 % |
| Circumference | 85.6" | 87.3" | +2.0 % |
| Revs per mile | 741 | 726 | -2.0 % |
| Axle height | 13.62" | 13.89" | +7.0 mm |
| Approved rim width | 9.5–12.5" | 10–13" | overlap 10–12.5" |
Both are approved on a rim 10" to 12.5" wide. If yours is in that band, this is a tire change and nothing else.
What the speedometer will say
Calibrated for 335/35R18. Fit 355/35R18 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 30.6 mph | +0.6 |
| 50 mph | 51.0 mph | +1.0 |
| 70 mph | 71.4 mph | +1.4 |
| 90 mph | 91.8 mph | +1.8 |
The odometer drifts with it. Ten thousand miles on the dial are really 10,202 on the road, so it under-counts by 202. At a true 70 mph the first turns 864 times a minute, the second 847.